those ebay guides look fine to me. they are the same looking as the nissan ones. both nissan and the ebay set (that link shows a set that looks high quality) have the same designed push-clip plastic guides that clip to metal rails. but if there are molded type(plastic
guide material bonded to the metal), those are the best quality to get. maybe nissan doesn't make it? i know they make it for the L-series bonded, but the later engines they go cheap...
you can see individual parts here.
http://www.partsamerica.com/Pr...Set=A